High-added-value recovery method for copper in black powder lithium-rich copper-containing pickle liquor of retired lithium iron phosphate battery

Abstract

The invention relates to a high-added-value recovery method for copper in black powder lithium-rich copper-containing pickle liquor of a decommissioned lithium iron phosphate battery, and belongs to the technical field of lithium ion batteries and solid waste resource utilization. The lithium-rich copper-containing pickle liquor is subjected to targeted sulfuration and separation treatment to obtain acidic sulfuration slag and lithium-rich pickle liquor, the acidic sulfuration slag is subjected to water washing treatment to obtain sulfuration slag and dilute acid liquor, and the sulfuration slag is subjected to desulfurization treatment to obtain nano copper sulfide and a sulfur-containing solution. The method is simple to operate, high in lithium recovery rate, high in additional value of copper byproducts, high in overall economic value and suitable for black powder pickle liquor of various retired lithium iron phosphate batteries.

Description

Technical Field

[0001] This invention relates to a high-value-added method for recovering copper from lithium-rich copper-containing acid leaching solution of retired lithium iron phosphate battery black powder, belonging to the technical field of lithium-ion battery and solid waste resource utilization. Background Technology

[0002] Lithium-ion batteries, with their advantages of high energy density, long cycle life, and lightweight design, have become core components of new energy power and energy storage equipment, playing a crucial role in the development of green energy. Among them, lithium iron phosphate batteries, with their core advantages of safety, cost, and lifespan, firmly occupy a dominant position in the power battery market with a market share exceeding 80%. However, the lifespan of lithium iron phosphate batteries is only 5-8 years, and a large number of retired batteries urgently need to be recycled. Improper disposal of retired lithium iron phosphate batteries will not only release heavy metals and produce highly toxic gases such as hydrogen fluoride and carbon monoxide, causing environmental pollution, but also waste key metal resources (lithium, cobalt, nickel, aluminum, etc.) contained in the batteries. The resource utilization of retired lithium iron phosphate batteries is a key issue for the healthy development of the battery industry.

[0003] Hydrometallurgical technology is one of the important technologies for the resource utilization of retired lithium-ion batteries. For the black powder from retired lithium iron phosphate batteries, an acid-oxidation method is generally used to leach various metal elements, obtaining a lithium-rich acid leachate containing impurities such as copper, aluminum, iron, and phosphorus. High-valence metal ions have a significant impact on lithium recovery. The mainstream method for copper removal is chemical precipitation, which involves directly adding a precipitant to separate copper and aluminum ions in the lithium-rich acid leachate through precipitation. However, depending on the precipitant and precipitation process design, this method easily leads to varying degrees of waste of lithium, iron, copper, and other metal elements, reducing economic efficiency.

[0004] In the method of removing copper from retired lithium-ion battery black powder through acid leaching, the black powder includes lithium iron phosphate black powder and ternary black powder. Patent CN119263239A uses sodium formaldehyde sulfide (sodium dimethyl dithiocarbamate) for copper removal. Sodium formaldehyde sulfide releases sulfur ions slowly, resulting in a long reaction time. Furthermore, this method uses organic reagents, making waste liquid treatment difficult and easily causing environmental pollution. Patents CN111129632B, CN115818603B, and CN117963866A all remove copper by adding sulfide salt powder to the acid leaching solution. This method easily leads to localized over-alkalinity of the solution and excessive accumulation of sulfur ions, causing side reactions between iron, nickel, cobalt, manganese, and other ions and hydroxide and sulfur ions. The by-products have low added value and cause adsorption and entrainment of lithium ions, ultimately resulting in the waste of key metal resources. Patent CN108232351B describes a method for removing copper by adding sodium sulfide solution to the leaching solution and introducing hydrogen sulfide gas. While this method improves copper removal efficiency, it is difficult to operate, hazardous (due to the large-scale use of toxic gases), and still cannot avoid the problems of localized over-alkalinity and excessive sulfur ion accumulation. As can be seen from the above patents, the sulfidation method for removing copper from retired lithium-ion battery black powder acid leaching solutions has a certain degree of applicability, but research on sulfidation methods for removing copper from retired lithium iron phosphate batteries is limited.

[0005] In summary, existing sulfidation processes for copper removal from retired lithium iron phosphate battery black powder leaching solutions result in low lithium recovery rates and low added value of copper byproducts. Furthermore, the potential impacts of factors such as the leaching solution environment, type of sulfiding agent, storage state, and external environment on lithium recovery rates and copper byproducts have not been thoroughly investigated. Therefore, inventing a high-value-added copper recovery method from retired lithium iron phosphate battery black powder leaching solutions is of significant importance in this field. Summary of the Invention

[0006] In view of this, the present invention aims to provide a high-value-added method for recovering copper from the acid leaching solution of retired lithium iron phosphate battery black powder. This method is simple to operate, has a high lithium recovery rate, produces high-value-added copper by-products, and has high overall economic value. It is applicable to various types of retired lithium iron phosphate battery black powder acid leaching solutions, and contributes to the recycling of various energy metals and valuable products. It has good environmental, economic, and social benefits and broad prospects for industrialization.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows.

[0008] A method for high-value-added copper recovery from lithium-rich copper-containing acid leaching solution of retired lithium iron phosphate battery black powder, the method steps include:

[0009] (1) Targeted sulfidation: At temperatures below 80°C, a sulfide salt solution is added dropwise to a lithium-rich copper-containing acid leaching solution and stirred for a targeted sulfidation reaction of more than 10 minutes. After the reaction is completed, the solid and liquid are separated to obtain acidic sulfide slag and lithium-rich acid leaching solution. The ratio of the amount of sulfur in the sulfide salt solution to the sum of the amounts of copper and iron in the acid leaching solution is 2 to 10:1. The concentration of the sulfide salt solution is less than or equal to 5 mol / L, the dropping rate of the sulfide salt solution is less than or equal to 50 mL / min, and the stirring rate is greater than or equal to 300 rpm.

[0010] (2) Water washing: The acidic sulfide slag is washed with water and the solid-liquid separation is performed to obtain sulfide slag and dilute acid solution;

[0011] (3) Desulfurization: The sulfide slag is added to an organic solvent for desulfurization treatment. After the treatment, the solid and liquid are separated to obtain nano copper sulfide and sulfur-containing solution.

[0012] Preferably, in step (1), the lithium-rich copper-containing acid leaching solution contains Li + Cu 2+ Al 3+ Fe 3+ and PO4 3- .

[0013] Preferably, in step (1), the sulfide salt is one or more of sodium sulfide, potassium sulfide and ammonium sulfide.

[0014] Preferably, in step (1), the concentration of the sulfide salt solution is 0.001 to 5 mol / L, and the dropping rate is 0.1 to 50 mL / min.

[0015] Preferably, in step (1), the targeted vulcanization reaction temperature is 0-80℃ and the reaction time is 10-720 min.

[0016] Preferably, in step (1), the stirring speed is 300 to 1200 rpm.

[0017] Preferably, in step (2), the washing solution is washed with water until the pH of the fresh washing solution is ≥6. The types of ions in the dilute acid solution obtained after summarizing the washing solutions are different from the types of ions in the lithium-rich copper-containing acid leaching solution (excluding Cu). 2+ (External) Same.

[0018] Preferably, the dilute acid solution described in step (2) is used to prepare the leaching agent. The prepared acid solution is used in the acid leaching process of black powder from retired lithium iron phosphate batteries.

[0019] Preferably, in step (3), the organic solvent is one or more of carbon disulfide, ethanol and dichloromethane.

[0020] Preferably, the sulfur-containing solution described in step (3) is evaporated to obtain elemental sulfur, and the organic solvent is recovered. The organic solvent can be reused in step (3). More preferably, the evaporation temperature is the boiling point of the organic solvent.

[0021] Beneficial effects

[0022] This invention provides a high-value-added method for recovering copper from the lithium-rich copper-containing acid leaching solution of retired lithium iron phosphate battery black powder. The method includes targeted sulfidation, water washing, desulfurization, evaporation, and leaching. The main process is as follows: the acid leaching solution undergoes targeted sulfidation and solid-liquid separation to obtain acidic sulfide slag and lithium-rich acid leaching solution; the acidic sulfide slag is washed to obtain sulfide slag and dilute acid solution (recycled for leaching); the sulfide slag is then desulfurized to obtain nano-copper sulfide and a sulfur-containing solution; the sulfur-containing solution is evaporated to obtain elemental sulfur (and the organic solvent is recovered). The method provided by this invention can effectively achieve high-value-added copper recovery from the acid leaching solution of retired lithium iron phosphate battery black powder, with a lithium element retention rate greater than 98.5%, a nano-copper sulfide purity greater than 99.5%, and the solution used in the process is recyclable, realizing the resource utilization of the acid leaching solution of retired lithium iron phosphate battery black powder.

[0023] This invention provides a method for high-value-added copper recovery from lithium-rich copper-containing acid leaching solutions of retired lithium iron phosphate battery black powder, targeting the main reaction equation of the sulfidation process as Cu 2+ +S 2– →CuS(s), 2Fe 3+ +S 2– →2Fe 2+ +S(s), a possible side reaction is Fe 3+ +3OH – →Fe(OH)3 (colloid), Al 3+ +3OH – → Al(OH)3, Fe 3+ + PO4 3– → FePO4(s), Fe 2+ + S 2– → FeS (s), 2H + + S 2– → H2S (g), etc. Fe is preferentially reduced by adjusting reaction conditions and solution addition methods. 3+ This process achieves targeted copper removal. Strict control of the sulfide salt solution concentration, dropping rate, dosage, reaction temperature, time, and stirring speed is required. The resulting sulfide slag mainly consists of nano-copper sulfide and elemental sulfur. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the process flow for a high-value-added copper recovery method from the copper-rich acid leaching solution of retired lithium iron phosphate battery black powder, as described in this invention.

[0025] Figure 2 The XRD test results of the sulfide slag described in this invention are shown.

[0026] Figure 3 The results are SEM test results of the sulfided slag described in this invention.

[0027] Specific implementation measures

[0028] The present invention will be further described in detail below with reference to specific embodiments.

[0029] like Figure 1 As shown, a method for high-value-added copper recovery from lithium-rich copper-containing acid leaching solution of retired lithium iron phosphate battery black powder includes the following steps:

[0030] (1) Targeted sulfidation: A certain proportion of sulfide salt solution is added to the lithium-rich copper-containing acid leaching solution at a rate of 0.1-50 mL / min for targeted sulfidation treatment, with precise control of reaction conditions such as stirring speed, reaction temperature, and time. After the reaction is completed, solid and liquid are separated to obtain acidic sulfide slag and lithium-rich acid leaching solution.

[0031] (2) Water washing: The acidic sulfide slag is washed with water. After the treatment, the solid and liquid are separated to obtain sulfide slag and dilute acid solution.

[0032] (3) Desulfurization: The sulfide slag is added to an organic solvent for desulfurization treatment. After the treatment, the solid and liquid are separated to obtain nano copper sulfide and sulfur-containing solution.

[0033] (4) Evaporation: The sulfur-containing solution is evaporated. After the treatment is completed, the organic solvent is recovered and reused in step (3) to obtain elemental sulfur.

[0034] (5) Used for leaching: The dilute acid solution obtained in step (2) is used for the preparation of leaching agent, and the prepared acid solution is used for the acid leaching process of black powder from retired lithium iron phosphate batteries.

[0035] In some instances, in step (1), Li must be present in the lithium-rich copper-containing acid leaching solution. + Cu 2+ Al 3+ Fe 3+ PO4 3- Plasma. Among them, Al... 3+ The content is much smaller than that of Fe. 3+ Cu 2+ High-valence metal ions.

[0036] In some instances, in step (1), the sulfide salt is one of sodium sulfide, potassium sulfide, or ammonium sulfide.

[0037] In some instances, during the targeted sulfidation in step (1), the concentration of the sulfide salt solution is 0.001–5 mol / L, for example, it can be 0.001 mol / L, 0.005 mol / L, 0.01 mol / L, 0.05 mol / L, 0.1 mol / L, 0.5 mol / L, 1 mol / L, 2 mol / L, 3 mol / L, 5 mol / L, etc.

[0038] In some instances, during the targeted sulfidation in step (1), the dripping rate of the sulfide salt solution is 0.1 to 50 mL / min, for example, it can be 0.1 mL / min, 0.5 mL / min, 1 mL / min, 2 mL / min, 3 mL / min, 4 mL / min, 5 mL / min, 6 mL / min, 8 mL / min, 10 mL / min, 20 mL / min, 30 mL / min, 40 mL / min, 50 mL / min, etc.

[0039] In some instances, during step (1) of targeted sulfidation, the ratio of the amount of sulfur in the sulfide salt solution to the sum of the amounts of copper and iron in the lithium-rich copper-containing acid leaching solution is 2 to 10:1. For example, it can be 2:1, 2.5:1, 3:1, 4:1, 5:1, 6:1, 8:1, 10:1, etc.

[0040] In some instances, during the targeted vulcanization in step (1), the reaction temperature is between 0 and 80°C. For example, it can be 0°C, 10°C, 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, etc.

[0041] In some instances, during the targeted vulcanization in step (1), the reaction time is 10 to 720 min. For example, it can be 10 min, 30 min, 60 min, 90 min, 120 min, 180 min, 240 min, 300 min, 360 min, 420 min, 540 min, 720 min, etc.

[0042] In some instances, during the targeted vulcanization in step (1), the stirring speed is 300–1200 rpm. For example, it can be 300 rpm, 400 rpm, 500 rpm, 600 rpm, 700 rpm, 800 rpm, 900 rpm, 1000 rpm, 1100 rpm, 1200 rpm, etc.

[0043] In some instances, in step (2), the water washing effect is that the pH of the fresh washing solution is ≥6.

[0044] In some instances, in step (2), the types of ions in the dilute acid solution obtained after summarizing the washing solutions are different from the types of ions in the lithium-rich copper-containing acid leaching solution (except for Cu). 2+ (External) Same.

[0045] In some instances, in step (3), the organic solvent is one or more of carbon disulfide, ethanol, and dichloromethane.

[0046] In some instances, in step (4), when the organic solvent is carbon disulfide, the evaporation temperature is selected as 50°C; when the organic solvent is ethanol, the evaporation temperature is selected as 80°C; and when the organic solvent is dichloromethane, the evaporation temperature is selected as 40°C.

[0047] Retired lithium iron phosphate batteries mainly consist of a battery casing, positive electrode material (lithium iron phosphate), negative electrode material (graphite), current collector (copper foil, aluminum foil), separator, lithium salt electrolyte, binder, and conductive agent. Industrially, through pretreatment steps such as discharge, mechanical crushing, sieving, and calcination, most of the aluminum foil can be separated, and the separator, lithium salt electrolyte, binder, and conductive agent can be decomposed to obtain a black powder material containing lithium iron phosphate, graphite, copper foil, and aluminum foil. In the following examples, the lithium-rich copper-containing acid leaching solution of retired lithium iron phosphate battery black powder was prepared by the following method: Leaching agents with sulfuric acid and hydrogen peroxide concentrations of 0.30 mol / L and 2.18 mol / L, respectively, were prepared. The solid-liquid ratio of black powder material to leaching agent was 10 g: 115 mL. After the leaching agent was heated to 60°C, the black powder material was added, and the reaction was carried out at 60°C and 400 rpm for 3 hours to obtain a lithium-rich copper-containing acid leaching solution and acid leaching residue.

[0048] Example 1

[0049] This embodiment provides a high-value-added method for recovering copper from lithium-rich copper-containing acid leaching solution of retired lithium iron phosphate battery black powder. The steps are as follows:

[0050] (1) Take the lithium-rich copper-containing acid leaching solution of retired lithium iron phosphate battery black powder (containing Li) + Cu 2+ Al 3+ Fe 3+ PO4 3- A 5 mol / L ammonium sulfide solution was prepared, with the ratio of sulfur in the solution to the sum of copper and iron in the lithium-rich copper-containing acid leaching solution being 2:1. The reaction temperature was set at 80℃ and the stirring speed at 700 rpm. The prepared ammonium sulfide solution was added dropwise to the lithium-rich copper-containing acid leaching solution at a rate of 4 mL / min, and the reaction was allowed to proceed for 720 min. After solid-liquid separation, acidic sulfide slag and lithium-rich acid leaching solution were obtained.

[0051] (2) Water washing: The acidic sulfide slag is washed with water. After the treatment, the solid and liquid are separated to obtain sulfide slag and dilute acid solution.

[0052] (3) Desulfurization: The sulfidation slag is added to carbon disulfide solvent. After the treatment is completed, solid-liquid separation is performed to obtain nano copper sulfide and sulfur-containing solution.

[0053] (4) Evaporation: The sulfur-containing solution is evaporated at a temperature of 50°C. After the treatment, elemental sulfur can be obtained and carbon disulfide solvent can be recovered.

[0054] (5) Used as a leaching agent: The dilute acid solution obtained in step (2) is used to prepare an acidic leaching agent, and the prepared leaching agent is used in the acid leaching process of black powder from retired lithium iron phosphate batteries.

[0055] In this embodiment, after targeted sulfidation of the lithium-rich copper-containing acid leaching solution, the copper impurity removal rate was 100%, the aluminum retention rate was 100%, the iron retention rate was 99.2%, the phosphorus retention rate was 97.9%, and the lithium retention rate was 98.3%. The nano-copper sulfide obtained after desulfurization of the sulfidation slag has a purity of 99.6%, which can be used as a high-performance functional material precursor for applications in solar cells, photocatalytic degradation of pollutants, and novel battery electrode materials. This example achieves precise copper sulfidation precipitation in the acid leaching solution of retired lithium iron phosphate battery black powder, obtaining lithium-rich acid leaching solution, and synergistically recovering high-value-added nano-copper sulfide, thus realizing high-value-added copper recovery from the acid leaching solution of retired lithium iron phosphate battery black powder.

[0056] Example 2

[0057] This embodiment provides a method for high-value-added recovery of copper from copper-containing lithium-rich acid leaching solution of retired lithium iron phosphate battery black powder, the steps of which are as follows:

[0058] (1) Take the lithium-rich copper-containing acid leaching solution of retired lithium iron phosphate battery black powder (containing Li) + Cu 2+ Al 3+ Fe 3+ PO4 3- A sodium sulfide solution with a concentration of 0.001 mol / L was prepared, with the ratio of sulfur content in the solution to the sum of copper and iron content in the lithium-rich copper-containing acid leaching solution being 4:1. The reaction temperature was set at 20℃ and the stirring speed at 1200 rpm. The prepared sodium sulfide solution was added dropwise to the lithium-rich copper-containing acid leaching solution at a rate of 0.1 mL / min, and the reaction was allowed to proceed for 180 min. After solid-liquid separation, acidic sulfide slag and lithium-rich acid leaching solution were obtained.

[0059] (2) Water washing: The acidic sulfide slag is subjected to water washing treatment. After the treatment, solid and liquid are separated to obtain sulfide slag and dilute acid solution. The XRD and SEM test results of the sulfide slag are shown in Figure 2-3.

[0060] (3) Desulfurization: The sulfidation slag is added to carbon disulfide solvent. After the treatment is completed, solid-liquid separation is performed to obtain nano copper sulfide and sulfur-containing solution.

[0061] (4) Evaporation: The sulfur-containing solution is evaporated at a temperature of 50°C. After the treatment, elemental sulfur can be obtained and carbon disulfide solvent can be recovered.

[0062] (5) Used as a leaching agent: The dilute acid solution obtained in step (2) is used to prepare an acidic leaching agent, and the prepared leaching agent is used in the acid leaching process of black powder from retired lithium iron phosphate batteries.

[0063] In this embodiment, after targeted sulfidation of the lithium-rich copper-containing acid leaching solution, the copper impurity removal rate was 100%, the aluminum retention rate was 100%, the iron retention rate was 99.8%, the phosphorus retention rate was 99.8%, and the lithium retention rate was 99.9%. The nano-copper sulfide obtained after desulfurization of the sulfidation slag has a purity of 99.9%, which can be used as a high-performance functional material precursor for applications in solar cells, photocatalytic degradation of pollutants, and novel battery electrode materials. This example achieves precise copper sulfidation precipitation in the acid leaching solution of retired lithium iron phosphate battery black powder, obtaining lithium-rich acid leaching solution, and synergistically recovering high-value-added nano-copper sulfide, thus realizing high-value-added copper recovery from the acid leaching solution of retired lithium iron phosphate battery black powder.

[0064] Example 3

[0065] This embodiment provides a high-value-added method for recovering copper from lithium-rich copper-containing acid leaching solution of retired lithium iron phosphate battery black powder. The steps are as follows:

[0066] (1) Take the lithium-rich copper-containing acid leaching solution of retired lithium iron phosphate battery black powder (containing Li) + Cu 2+ Al 3+ Fe 3+ PO4 3- A 0.05 mol / L potassium sulfide solution was prepared, with the ratio of sulfur content in the solution to the sum of copper and iron content in the lithium-rich copper-containing acid leaching solution being 10:1. The reaction temperature was set to 0℃ and the stirring speed to 300 rpm. The prepared potassium sulfide solution was added dropwise to the lithium-rich copper-containing acid leaching solution at a rate of 50 mL / min, and the reaction was allowed to proceed for 10 min. Solid-liquid separation was then performed to obtain acidic sulfide slag and the lithium-rich acid leaching solution.

[0067] (2) Water washing: The acidic sulfide slag is washed with water. After the treatment, the solid and liquid are separated to obtain sulfide slag and dilute acid solution.

[0068] (3) Desulfurization: The sulfidation slag is added to carbon disulfide solvent. After the treatment is completed, solid-liquid separation is performed to obtain nano copper sulfide and sulfur-containing solution.

[0069] (4) Evaporation: The sulfur-containing solution is evaporated at a temperature of 50°C. After the treatment, elemental sulfur can be obtained and carbon disulfide solvent can be recovered.

[0070] (5) Used as a leaching agent: The dilute acid solution obtained in step (2) is used to prepare an acidic leaching agent, and the prepared leaching agent is used in the acid leaching process of black powder from retired lithium iron phosphate batteries.

[0071] In this embodiment, after targeted sulfidation of the lithium-rich copper-containing acid leaching solution, the copper impurity removal rate was 100%, the aluminum retention rate was 100%, the iron retention rate was 99.1%, the phosphorus retention rate was 98.9%, and the lithium retention rate was 99.1%. The nano-copper sulfide obtained after desulfurization of the sulfide slag has a purity of 99.8%, which can be used as a high-performance functional material precursor for applications in solar cells, photocatalytic degradation of pollutants, and novel battery electrode materials. This example achieves precise copper sulfidation precipitation in the acid leaching solution of retired lithium iron phosphate battery black powder, obtaining lithium-rich acid leaching solution, and synergistically recovering high-value-added nano-copper sulfide, thus realizing high-value-added copper recovery from the acid leaching solution of retired lithium iron phosphate battery black powder.

[0072] Example 4

[0073] This embodiment provides a high-value-added method for recovering copper from lithium-rich copper-containing acid leaching solution of retired lithium iron phosphate battery black powder. The steps are as follows:

[0074] (1) Take the lithium-rich copper-containing acid leaching solution of retired lithium iron phosphate battery black powder (containing Li) + Cu 2+ Al 3+ Fe 3+ PO4 3- A 5 mol / L ammonium sulfide solution was prepared, with the ratio of sulfur content in the solution to the sum of copper and iron content in the lithium-rich copper-containing acid leaching solution being 2.5:1. The reaction temperature was set at 80℃ and the stirring speed at 800 rpm. The prepared ammonium sulfide solution was added dropwise to the lithium-rich copper-containing acid leaching solution at a rate of 8 mL / min, and the reaction was allowed to proceed for 720 min. After solid-liquid separation, acidic sulfide slag and lithium-rich acid leaching solution were obtained.

[0075] (2) Water washing: The acidic sulfide slag is washed with water. After the treatment, the solid and liquid are separated to obtain sulfide slag and dilute acid solution.

[0076] (3) Desulfurization: The sulfide slag is added to an ethanol solvent. After the treatment is completed, the nano copper sulfide and sulfur-containing solution are obtained through solid-liquid separation.

[0077] (4) Evaporation: The sulfur-containing solution is evaporated at a temperature of 80°C. After the treatment, elemental sulfur is obtained and the ethanol solvent is recovered.

[0078] (5) Used as a leaching agent: The dilute acid solution obtained in step (2) is used to prepare an acidic leaching agent, and the prepared leaching agent is used in the acid leaching process of black powder from retired lithium iron phosphate batteries.

[0079] In this embodiment, after targeted sulfidation of the lithium-rich copper-containing acid leaching solution, the copper impurity removal rate was 100%, the aluminum retention rate was 100%, the iron retention rate was 99.4%, the phosphorus retention rate was 99.4%, and the lithium retention rate was 99.2%. The nano-copper sulfide obtained after desulfurization of the sulfide slag has a purity of 99.9%, which can be used as a high-performance functional material precursor for applications in solar cells, photocatalytic degradation of pollutants, and novel battery electrode materials. This example achieves precise copper sulfidation precipitation in the acid leaching solution of retired lithium iron phosphate battery black powder, obtaining lithium-rich acid leaching solution, and synergistically recovering high-value-added nano-copper sulfide, thus realizing high-value-added copper recovery from the acid leaching solution of retired lithium iron phosphate battery black powder.

[0080] Example 5

[0081] This embodiment provides a high-value-added method for recovering copper from lithium-rich copper-containing acid leaching solution of retired lithium iron phosphate battery black powder. The steps are as follows:

[0082] (1) Take the lithium-rich copper-containing acid leaching solution of retired lithium iron phosphate battery black powder (containing Li) + Cu 2+ Al 3+ Fe 3+ PO4 3- A sodium sulfide solution with a concentration of 0.005 mol / L was prepared, with the ratio of sulfur content in the solution to the sum of copper and iron content in the lithium-rich copper-containing acid leaching solution being 5:1. The reaction temperature was set at 50℃ and the stirring speed at 1200 rpm. The prepared ammonium sulfide solution was added dropwise to the lithium-rich copper-containing acid leaching solution at a rate of 0.1 mL / min, and the reaction was allowed to proceed for 120 min. After solid-liquid separation, acidic sulfide slag and lithium-rich acid leaching solution were obtained.

[0083] (2) Water washing: The acidic sulfide slag is washed with water. After the treatment, the solid and liquid are separated to obtain sulfide slag and dilute acid solution.

[0084] (3) Desulfurization: The sulfide slag is added to an ethanol solvent. After the treatment is completed, the nano copper sulfide and sulfur-containing solution are obtained through solid-liquid separation.

[0085] (4) Evaporation: The sulfur-containing solution is evaporated at a temperature of 80°C. After the treatment, elemental sulfur is obtained and the ethanol solvent is recovered.

[0086] (5) Used as a leaching agent: The dilute acid solution obtained in step (2) is used to prepare an acidic leaching agent, and the prepared leaching agent is used in the acid leaching process of black powder from retired lithium iron phosphate batteries.

[0087] In this embodiment, after targeted sulfidation of the lithium-rich copper-containing acid leaching solution, the copper impurity removal rate was 100%, the aluminum retention rate was 100%, the iron retention rate was 99.2%, the phosphorus retention rate was 99.2%, and the lithium retention rate was 98.9%. The nano-copper sulfide obtained after desulfurization of the sulfide slag has a purity of 99.8%, which can be used as a high-performance functional material precursor for applications in solar cells, photocatalytic degradation of pollutants, and novel battery electrode materials. This example achieves precise copper sulfidation precipitation in the acid leaching solution of retired lithium iron phosphate battery black powder, obtaining lithium-rich acid leaching solution, and synergistically recovering high-value-added nano-copper sulfide, thus realizing high-value-added copper recovery from the acid leaching solution of retired lithium iron phosphate battery black powder.

[0088] Example 6

[0089] This embodiment provides a high-value-added method for recovering copper from lithium-rich copper-containing acid leaching solution of retired lithium iron phosphate battery black powder. The steps are as follows:

[0090] (1) Take the lithium-rich copper-containing acid leaching solution of retired lithium iron phosphate battery black powder (containing Li) + Cu 2+ Al 3+ Fe 3+ PO4 3- A 1 mol / L potassium sulfide solution was prepared, with the ratio of sulfur in the solution to the sum of copper and iron in the lithium-rich copper-containing acid leaching solution being 6:1. The reaction temperature was set at 10℃ and the stirring speed at 300 rpm. The prepared potassium sulfide solution was added dropwise to the lithium-rich copper-containing acid leaching solution at a rate of 40 mL / min, and the reaction was allowed to proceed for 30 min. After solid-liquid separation, acidic sulfide slag and lithium-rich acid leaching solution were obtained.

[0091] (2) Water washing: The acidic sulfide slag is washed with water. After the treatment, the solid and liquid are separated to obtain sulfide slag and dilute acid solution.

[0092] (3) Desulfurization: The sulfide slag is added to an ethanol solvent. After the treatment is completed, the nano copper sulfide and sulfur-containing solution are obtained through solid-liquid separation.

[0093] (4) Evaporation: The sulfur-containing solution is evaporated at a temperature of 80°C. After the treatment, elemental sulfur is obtained and the ethanol solvent is recovered.

[0094] (5) Used as a leaching agent: The dilute acid solution obtained in step (2) is used to prepare an acidic leaching agent, and the prepared leaching agent is used in the acid leaching process of black powder from retired lithium iron phosphate batteries.

[0095] In this embodiment, after targeted sulfidation of the lithium-rich copper-containing acid leaching solution, the copper impurity removal rate was 100%, the aluminum retention rate was 100%, the iron retention rate was 99.3%, the phosphorus retention rate was 98.6%, and the lithium retention rate was 99.5%. The nano-copper sulfide obtained after desulfurization of the sulfidation slag has a purity of 99.5% and can be used as a high-performance functional material precursor for applications in solar cells, photocatalytic degradation of pollutants, and novel battery electrode materials. This example achieves precise copper sulfidation precipitation in the acid leaching solution of retired lithium iron phosphate battery black powder, obtaining lithium-rich acid leaching solution, and synergistically recovering high-value-added nano-copper sulfide, thus realizing high-value-added copper recovery from the acid leaching solution of retired lithium iron phosphate battery black powder.

[0096] Comparative Example 1

[0097] Except for setting the concentration of the sulfide salt solution for targeted sulfidation in step (1) to 6 mol / L, the other steps and conditions are the same as in Example 2.

[0098] In this comparative example, after targeted sulfidation of the lithium-rich copper-containing acid leaching solution, the copper impurity removal rate was 95.9%, the aluminum retention rate was 96.2%, the iron retention rate was 80.3%, the phosphorus retention rate was 82.9%, and the lithium retention rate was 80.4%. After desulfurization of the sulfidation slag, nano-copper sulfide with a purity of 75.8% was obtained.

[0099] Comparative Example 2

[0100] Except for setting the ratio of sulfur in the sulfide salt solution for targeted sulfidation in step (1) to copper in the lithium-rich copper-containing acid leaching solution to 12:1, all other steps and conditions are the same as in Example 2.

[0101] In this comparative example, after targeted sulfidation of the lithium-rich copper-containing acid leaching solution, the copper impurity removal rate was 100%, the aluminum retention rate was 81.3%, the iron retention rate was 71.4%, the phosphorus retention rate was 79.0%, and the lithium retention rate was 79.1%. After desulfurization of the sulfidation slag, the purity of the obtained nano-copper sulfide was 70.2%.

[0102] Comparative Example 3

[0103] Except for setting the reaction temperature for targeted vulcanization in step (1) to 90°C, the other steps and conditions are the same as in Example 2.

[0104] In this comparative example, after targeted sulfidation of the lithium-rich copper-containing acid leaching solution, the copper impurity removal rate was 81.6%, the aluminum retention rate was 85.4%, the iron retention rate was 70.2%, the phosphorus retention rate was 70.7%, and the lithium retention rate was 68.9%, accompanied by the generation of a large amount of hydrogen sulfide gas. After desulfurization of the sulfide slag, nano-copper sulfide with a purity of 67.7% was obtained.

[0105] Comparative Example 4

[0106] Except for setting the dripping rate of the sulfide salt solution for targeted sulfidation in step (1) to 70 mL / min, the other steps and conditions are the same as in Example 2.

[0107] In this comparative example, after targeted sulfidation of the lithium-rich copper-containing acid leaching solution, the copper impurity removal rate was 98.1%, the aluminum retention rate was 98.8%, the iron retention rate was 81.1%, the phosphorus retention rate was 82.4%, and the lithium retention rate was 79.4%. After desulfurization of the sulfidation slag, the purity of the obtained nano-copper sulfide was 84.3%.

[0108] Comparative Example 5

[0109] Except for setting the stirring speed for targeted vulcanization in step (1) to 100 rpm, the other steps and conditions are the same as in Example 2.

[0110] In this comparative example, after targeted sulfidation of the lithium-rich copper-containing acid leaching solution, the copper impurity removal rate was 94.5%, the aluminum retention rate was 99.1%, the iron retention rate was 90.4%, the phosphorus retention rate was 92.3%, and the lithium retention rate was 82.7%. After desulfurization of the sulfidation slag, the purity of the obtained nano-copper sulfide was 86.2%.

[0111] Comparative Example 6

[0112] Except for setting the reaction time for targeted vulcanization in step (1) to 2 min, the other steps and conditions are the same as in Example 2.

[0113] In this comparative example, after targeted sulfidation of the lithium-rich copper-containing acid leaching solution, the copper impurity removal rate was 91.6%, the aluminum retention rate was 92.6%, the iron retention rate was 94.3%, the phosphorus retention rate was 92.1%, and the lithium retention rate was 81.6%. After desulfurization of the sulfidation slag, the purity of the nano-copper sulfide obtained was 92.6%.

[0114] A comparison of Examples 1-8 shows that when the reaction parameters are set within the reaction conditions of this invention, targeted sulfidation can proceed fully, with a copper impurity removal rate of 100%, a lithium retention rate of over 98.5%, and a purity of over 99.5% for the nano-copper sulfide obtained after desulfurization. Ultimately, this achieves efficient removal of copper impurities from black powder acid leaching solution and synergistic recovery of high-value-added nano-copper sulfide.

[0115] A comparison of Example 2 and Comparative Example 1 shows that when the sulfide salt concentration is greater than 5 mol / L during targeted sulfidation, the local solution becomes overly alkaline and sulfur ions become excessively enriched, leading to the participation of some aluminum, iron, and phosphorus in the reaction. This results in incomplete sulfidation, with a copper removal rate of only 95.9%, and aluminum, iron, and phosphorus retention rates of 96.2%, 80.3%, and 82.9%, respectively. The double-layer structure on the precipitate surface adsorbs lithium ions, resulting in a lithium retention rate of only 80.4%. After water washing and desulfurization, the purity of the obtained nano-copper sulfide is 75.8%.

[0116] A comparison of Example 2 and Comparative Example 2 shows that when the ratio of sulfur in the sulfide salt solution to copper in the lithium-rich copper-containing acid leaching solution is greater than 10:1 during targeted sulfidation, the lithium-rich copper-containing acid leaching solution is severely diluted, the pH of the solution rises sharply, aluminum and iron hydrolyze, and iron and phosphorus react to form iron phosphate precipitate. Excess sulfur ions react with iron, and copper is completely removed, but the retention rates of aluminum, iron, and phosphorus are 81.3%, 71.4%, and 79.0%, respectively, while the retention rate of lithium is only 79.1%. After water washing and desulfurization steps, the purity of the obtained nano-copper sulfide is 70.2%.

[0117] A comparison of Example 2 and Comparative Example 3 shows that when the reaction temperature exceeds 80°C during targeted sulfidation, a large amount of hydrogen sulfide gas is generated. Insufficient sulfur ions in the solution lead to incomplete copper removal through sulfidation, resulting in a copper removal rate of only 80.4%. High temperature promotes the hydrolysis of aluminum and iron, forming colloids, and iron begins to precipitate as hydrated iron phosphate. The retention rates of aluminum, iron, and phosphorus are 85.4%, 70.2%, and 70.7%, respectively. A large amount of lithium is adsorbed and entrained by the colloids, resulting in a lithium retention rate of only 68.9%. After water washing and desulfurization steps, the purity of the obtained nano-copper sulfide is 67.7%.

[0118] A comparison of Example 2 and Comparative Example 4 shows that when the dripping rate of the sulfide salt solution in targeted sulfidation exceeds 50 mL / min, localized over-alkaliness and excessive enrichment of sulfur ions occur, leading to insufficient sulfidation as some aluminum, iron, and phosphorus participate in the reaction. The copper impurity removal rate is only 98.1%, while the retention rates of aluminum, iron, and phosphorus are 98.8%, 81.1%, and 82.4%, respectively, and the lithium retention rate is only 79.4%. After water washing and desulfurization steps, the purity of the obtained nano-copper sulfide is 84.3%.

[0119] A comparison of Example 2 and Comparative Example 5 shows that when the stirring speed during targeted sulfidation is less than 300 rpm, the local solution becomes excessively alkaline and sulfur ions become excessively enriched. Some aluminum, iron, and phosphorus participate in the reaction, resulting in incomplete sulfidation and rapid agglomeration of copper sulfide precipitate. The copper removal rate is only 94.5%, while the retention rates of aluminum, iron, and phosphorus are 99.1%, 90.4%, and 92.3%, respectively, and the lithium retention rate is only 82.7%. After water washing and desulfurization steps, the purity of the obtained nano-copper sulfide is 86.2%.

[0120] A comparison of Example 2 and Comparative Example 6 shows that when the reaction time in targeted sulfidation is less than 10 minutes, the reaction is incomplete, and the solution is pale yellow. The copper impurity removal rate is only 91.6%, while the retention rates of aluminum, iron, and phosphorus are 92.6%, 94.3%, and 92.1%, respectively, and the lithium retention rate is only 81.6%. After water washing and desulfurization steps, the purity of the obtained nano-copper sulfide is 92.6%.

[0121] In summary, the invention includes, but is not limited to, the above embodiments. Any equivalent substitutions or partial improvements made under the spirit and principles of this invention shall be considered to be within the protection scope of this invention.

Claims

1. A method for high-value-added recovery of copper from lithium-rich copper-containing acid leaching solution of retired lithium iron phosphate battery black powder, characterized in that: The method steps include: (1) Targeted sulfuration: at 80℃ or below, a sulfuration salt solution is added dropwise into a lithium-rich copper-containing acid leaching solution and stirred to carry out a targeted sulfuration reaction for 10 min or more. After the reaction is completed, solid-liquid separation is carried out to obtain an acidic sulfuration residue and a lithium-rich acid leaching solution. In the sulfuration salt solution, the ratio of the amount of substance of sulfur to the sum of the amounts of substance of copper and iron in the acid leaching solution is 2-10:

1. The concentration of the sulfuration salt solution is less than or equal to 5 mol / L. The dropwise addition speed of the sulfuration salt solution is less than or equal to 50 mL / min. The stirring speed is greater than or equal to 300 rpm. (2) Water washing: the acidic sulfuration residue is subjected to water washing and solid-liquid separation to obtain a sulfuration residue and a dilute acid solution. (3) Desulfurization: the sulfuration residue is added into an organic solvent for desulfurization treatment. After the treatment is completed, solid-liquid separation is carried out to obtain nanometer copper sulfide and a sulfur-containing solution.

2. The high value-added recovery method of copper in the lithium-rich copper-containing acid leaching solution of the retired lithium iron phosphate sub-battery black powder according to claim 1, characterized in that: In step (1), the lithium-rich copper-containing acid leach solution contains Li + , Cu 2+ , Al 3+ , Fe 3+ , and PO4 3- .

3. The high value-added recovery method of copper in the retired lithium iron phosphate sub-battery black powder rich in lithium and copper acid leaching solution according to claim 1 or 2, characterized in that: In step (1), the sulfuration salt is one or more of sodium sulfide, potassium sulfide and ammonium sulfide.

4. The high value-added recovery method of copper in the retired lithium iron phosphate sub-battery black powder rich in lithium and copper acid leaching solution according to claim 1 or 2, characterized in that: In step (1), the concentration of the sulfuration salt solution is 0.001-5 mol / L. The dropwise addition speed is 0.1-50 mL / min.

5. The high value-added recovery method of copper in the retired lithium iron phosphate sub-battery black powder lithium-rich copper-containing acid leaching solution according to claim 1 or 2, characterized in that: In step (1), the temperature of the targeted sulfuration reaction is 0-80℃. The reaction time is 10-720 min.

6. The high value-added recovery method of copper in the retired lithium iron phosphate sub-battery black powder rich in lithium and copper acid leaching solution according to claim 1 or 2, characterized in that: In step (1), the stirring speed is 300-1200 rpm.

7. The high value-added recovery method of copper in the retired lithium iron phosphate sub-battery black powder rich in lithium and copper acid leaching solution according to claim 1 or 2, characterized in that: In step (2), the water washing is carried out until the pH of the fresh washing solution is greater than or equal to 6.

8. The high value-added recovery method of copper in the lithium-rich copper-containing acid leaching solution of the decommissioned lithium iron phosphate sub-battery black powder according to claim 1, characterized in that: The dilute acid solution in step (2) is used for preparation of a leaching agent.

9. The high value-added recovery method of copper in the lithium-rich copper-containing acid leaching solution of the decommissioned lithium iron phosphate sub-battery black powder according to claim 1, characterized in that: In step (3), the organic solvent is one or more of carbon disulfide, ethanol and dichloromethane.

10. The high value-added recovery method of copper in the retired lithium iron phosphate sub-battery black powder lithium-rich copper-containing acid leaching solution according to claim 1 or 9, characterized in that: The sulfur-containing solution in step (3) is subjected to evaporation treatment to obtain elemental sulfur and recover the organic solvent. The evaporation temperature is preferably the boiling point of the organic solvent.

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